Skin Conditions, General | July 26, 2014 | Author: The Super Pharmacist
Why Do Human Beings Sweat? The main purpose of sweating is the regulation of body temperature. Sweating causes a decrease in core body temperature through evaporative cooling of liquid sweat at the skin surface.
All warm-blooded creatures, like mammals, must maintain a constant body temperature for survival. In cooler environments, this is accomplished by converting food into energy which generates heat. In hotter environments, cooling is achieved by means of sweating (humans), panting (dogs), licking (cats and rabbits), or bathing (pigs and elephants). Primates, such as humans, apes and monkeys, rely on sweating for temperature regulation much more than other animals.
There are two main types of sweat glands in humans. Eccrine and Apocrine
Eccrine glands secrete sweat through pores found in the palms of hands, soles of feet, and forehead. They secrete a clear, watery, odorless fluid containing small amounts of salt (sodium chloride). Eccrine sweat glands open through pores directly onto the surface of the skin, releasing sweat for rapid evaporation to cool the skin and lower body temperature.
Apocrine glands are present only under the arms and in the genital region. Although present from birth, they are nonfunctional until puberty. The apocrine sweat glands empty into hair follicles rather than directly onto the skin’s surface. The sweat produced by the apocrine glands contains lipids (fats) and proteins that mix with the sebaceous fluids in the hair follicles to reach the skin’s surface. Bacteria on the surface of the skin consume the lipids and proteins, creating waste byproducts that are responsible for the characteristic odor associated with sweating.
Hyperhidrosis is a medical condition in which a person sweats excessively and unpredictably. Hyperhidrosis can be divided into two main categories – local or general hyperhidrosis.
Local hyperhidrosis is usually limited to one or a few regions of the body. Most commonly, local hyperhidrosis affects the armpits, groin, hands, face and/or feet. These areas have higher concentrations of eccrine sweat glands than other areas of the body and may explain their involvement.
Hyperhidrosis can be further classified as primary or secondary.
Medical conditions that can cause secondary hyperhidrosis include:
Almost 3% of the general population, largely people aged between 25 and 64 years, experience hyperhidrosis. However, patients rarely seek a physician's help because many are unaware that they have a treatable medical disorder.
Regardless of the form, hyperhidrosis often causes great emotional distress and occupational disability for the people.
Social and business interactions can be affected.
For instance, if hyperhidrosis affects the hands, individuals avoid hand shaking due to sweaty palms.
Excessive sweating can cause individuals to avoid public speaking engagements for fear of embarrassment of sweating in front of an audience.
The physiology of hyperhidrosis is poorly understood. It is believed to be related to abnormal activation of the sympathetic nerves that supply both the eccrine and apocrine glands. It may also result from abnormalities anywhere along the pathway involved with sweat control, namely brain, spinal cord, peripheral nerves or the glands themselves.
There are several common treatments that can be tried to effectively reduce the impact of symptoms of excessive sweating, including the following:
Excessive sweating may be controlled with strong anti-perspirants, which plug the sweat ducts. Products containing 10% to 20% aluminum chloride hexahydrate are the first line of treatment for underarm sweating.
Medications may be taken orally to block the neurotransmitter, acetylcholine, from stimulating the sweat glands. Anticholinergics such as propantheline bromide, glycopyrrolate, oxybutynin, and benztropine are effective because the preglandular neurotransmitter for sweat secretion is acetylcholine (although the eccrine glands are also supplied by adrenergic nerve fibers containing catecholamines).
In addition, other systemic medications, such as sedatives and tranquilisers, indomethacin, and calcium channel blockers, may be beneficial in the treatment of palmoplantar (hand and foot) hyperhidrosis.
Iontophoresis consists of passing a direct current across the skin. This is most easily used for the palms and soles. Units can be purchased for use within the home.
In this procedure, the hands or feet are placed into tap water or tap water with anticholinergics, and then a gentle current of electricity is passed through the liquid. The electricity is gradually increased until the patient feels a light tingling sensation. The therapy lasts about 10 to 20 minutes and requires several sessions. The electric current is believed to disrupt the function of the sweat glands, but the exact mechanism of action is under debate. By using this machine a few times per week, dryness in the area of treatment can be obtained that can last for several weeks. Numerous agents have been used including tap water and anticholinergics; however, treatment with anticholinergic iontophoresis is more effective than tap water iontophoresis. In palmoplantar hyperhidrosis, the daily treatment of each palm or sole for 30 minutes at 15-20 mA with tap water iontophoresis is effective.
Botulinum toxin type A (Botox) is used to treat severe underarm sweating. This condition is called primary axillary hyperhidrosis. Botulinum toxin injections are effective because of their anticholinergic effects which block nerve conduction to the sweat glands.
A substantial increase in the duration of efficacy may be produced by repetitive injections in patients with primary palmar hyperhidrosis. Injections of botulinum toxin A reconstituted in lidocaine are associated with significantly reduced pain, which may be preferable for treating axillary hyperhidrosis.
Injections of botulinum toxin must be repeated at varying intervals to maintain long-term results.
Endoscopic thoracic sympathectomy (ETS) The nerve supply to the sweat glands can be interrupted by cutting or destroying the sympathetic nerves. This procedure is known as a sympathectomy. Sympathectomy has been used as a permanent effective treatment since 1920. Usually, it is reserved as the final treatment option. This procedure turns off the signal that tells the body to sweat excessively. It is usually performed on patients whose palms sweat much more heavily than normal. It may also be used to treat extreme sweating of the face. ETS does not work as well for those with excessive armpit sweating.
Underarm surgery This surgery removes the sweat glands in the armpits. Methods used include laser, curettage (scraping), excision (cutting), or liposuction. Compared with classic surgical excision, subcutaneous liposuction causes less disruption of the overlying skin, resulting in smaller surgical scars and a diminished area of hair loss.
Secondary hyperhidrosis can often be treated, although the right approach depends on the condition causing it. For instance, hyperhidrosis caused by an overactive thyroid may be resolved by treating the thyroid with medication or surgery. Excessive sweating caused by diabetes may disappear once glucose levels are under control.
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